Asymmetric initiated shaped charge and method for making a slot-like perforation

ABSTRACT

A shaped charge is configured to make a non-circular perforation into a casing. The shaped charge includes a case having a side wall that extends between an open top region and a base; an asymmetric initiation insert configured to fit within the case; an explosive material placed over the asymmetric initiation insert and in contact with the side wall of the case; and a liner placed over the explosive material, to hold the explosive material within the case. The asymmetric initiation insert has a body that includes first and second channels that extend from a bottom surface to a top surface of the body, so that a detonation at the bottom surface is directed to first and second initiation points, that correspond to the first and second channels.

BACKGROUND Technical Field

Embodiments of the subject matter disclosed herein generally relate to shaped charges and associated perforations made in the casing of a well, and more specifically, to a shaped charge that is configured to be asymmetrically initiated for generating a slot-like jet of material for perforating the casing to obtain a slot-like perforation profile.

Discussion of the Background

In the oil and gas field, once a well is drilled to a desired depth H relative to the surface, and the casing protecting the wellbore has been installed and cemented in place, it is time to connect the wellbore to the subterranean formation and to extract the oil and/or gas. This process of connecting the wellbore to the subterranean formation may include a step of plugging with a well a previously fractured stage of the well, a step of perforating a new stage of the casing with a perforating gun system (that includes plural guns) such that plural channels are formed to connect the subterranean formation to the inside of the casing, a step of removing the perforating gun system after all the desired stages have been perforated, and a step of pumping to the surface the oil that enters the casing through the formed plural channels.

However, after the oil pressure in the formation becomes smaller than the hydrostatic pressure in the well, the natural oil flow from the formation into the casing diminishes, and the oil production ceases, although oil is still trapped in the formation. For these wells, a fracturing operation may be applied to extend their lifespan. A typical fracturing operation uses a slurry of a proppant (sand) and a liquid (water), which is pumped into each stage at high rates. The slurry enters then through the holes (perforations) made by the gun system into the casing, into the channels made in the formation by the same gun systems and hydraulically fractures the formation to open up the channels and allow the remaining oil to flow into the casing.

The amount of the slurry that flows through each perforation made into the casing may vary based upon a variety of factors. For example, one such factor is the shape of the perforation. The shape of the perforation depends on the type of the shaped charged used in the gun system for perforating the casing. The typical shaped charge is shown in FIG. 1 and is symmetrical along the longitudinal axis Y. The shaped charge 100 has a case 110 that is made of metal and is itself symmetrical relative to the axis Y. The case 110 holds an explosive material 112, which is kept in place by a liner 114. The liner is typically made of a metallic material. Both the explosive material 112 and the liner 114 are also symmetrically distributed relative to the axis Y. The base 111 of the case 110 is filled with a detonation material 120, which is configured to detonate the explosive material 112. A hole 122 into the base 111 of the case 110 allows a detonator cable 130 or a booster material (not shown) to detonate the detonation material 120.

The problem with these symmetrical shaped charges is that there is only one initiation point A of the explosive material 112 and thus, when the liner 114 collapses due to the pressure generated by the explosion of the explosive material 112, the jet of material 140 formed from the liner 114 is very symmetrical about the longitudinal axis Y (i.e., is shaped as a cylinder), and this jet, when penetrating the casing (not shown) and the formation (not shown) would typically generate a round perforation and a round channel, respectively.

Having round perforations in the casing and/or round channels in the formation has been found over time to pose the following problem. Assuming that the diameter of the perforations is D1, and the average diameter of the particles in the slurry is D2, which is smaller than D1, over time, if the D1 is not at least six times larger than D2, the particles start to accumulate at the edge of the perforation and over time, they form a bridge, which diminishes if not suppresses the amount of the slurry that flows from the casing into the formation. This is undesirable because the fracturing operation relies on the slurry travelling at a desired rate from the casing into the formation.

To prevent this problem, there are efforts in the field to make slot-type perforations instead of round perforations. A slot-type perforation is understood herein to be a perforation or hole that is made in the casing with a shaped charge and has a shape more similar to a rectangle or square, i.e., a slot, than to a circle. In other words, a slot-type perforation is a non-circular perforation. To obtain slot-type perforations, various shaped charge manufacturers have tried to make the shaped charge non-symmetrical along the Y axis, by either manipulating the shape of the case, by providing plural initiation points by making corresponding plural holes into the case, or by adding various inserts in the explosive material to influence the shaped of the jet 140.

However, such approaches are complicated as they required to modify the case for making more initiation points, or to make an asymmetrical case, or to add various inserts in the explosive material. Further, such approaches are case specific, meaning that each shaped charge manufacturer has to modify differently its manufacturing process. Furthermore, these approaches cannot be used with the existing shaped charge's cases, and thus, require further investments and developing new manufacturing capabilities.

The slot-type perforations are also used for plug and abandonment operations. At the end of life of the well, special procedures are implemented for sealing the well and ensuring that the formations around the well are pressure isolated so that contamination between different formations is minimized. For these operations, non-circular slots are desired to be made in the casing of the well.

Thus, there is a need to form slot-type perforations into the well's casing with an existing shaped charge's case, and to achieve these results with an easy to manufacture shaped charge, that require inexpensive modifications when compared to a traditional shaped charge.

SUMMARY

According to an embodiment, there is a shaped charge for making a non-circular perforation into a casing. The shaped charge includes a case having a side wall that extends between an open top region and a base, an asymmetric initiation insert configured to fit within the case, an explosive material placed over the asymmetric initiation insert and in contact with the side wall of the case, and a liner placed over the explosive material, to hold the explosive material within the case. The asymmetric initiation insert has a body that includes first and second channels that extend from a bottom surface to a top surface of the body, so that a detonation at the bottom surface is directed to first and second initiation points, that correspond to the first and second channels.

According to another embodiment, there is a perforating gun for perforating a casing in a well and the perforating gun includes a casing and a shaped charge provided within the casing and configured to make a non-circular perforation into the casing. The shaped charge includes an asymmetric initiation insert having a body that includes first and second channels that extend from a bottom surface to a top surface of the body, so that a detonation at the bottom surface is directed to first and second initiation points, that correspond to the first and second channels. The first and second initiation points make the shaped charge for form a non-circular perforation into the casing.

According to still another embodiment, there is a method of manufacturing a shaped charge that generates a non-circular perforation in a casing. The method includes providing a case for the shaped charge; placing an asymmetric initiation insert within the case; orienting angularly the asymmetric initiation insert relative to the case to achieve a desired orientation of the non-circular perforation relative to the casing; placing an explosive material over the asymmetric initiation insert and in contact with a side wall of the case; and placing a liner over the explosive material, to hold the explosive material within the case. The asymmetric initiation insert has a body that includes first and second channels that extend from a bottom surface to a top surface of the body, so that a detonation at the bottom surface is directed to first and second initiation points at the top surface, which correspond to the first and second channels.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate one or more embodiments and, together with the description, explain these embodiments. In the drawings:

FIG. 1 illustrates a traditional shaped charge that is fully symmetrical around a longitudinal axis;

FIG. 2 illustrates a novel shaped charge that has an asymmetric initiation insert for generating a slot-type perforation in a casing;

FIG. 3 illustrates another novel shaped charge that has an asymmetric initiation insert for generating a slot-type perforation in a casing;

FIG. 4A illustrates the shaped charge having the asymmetric initiation insert with two channels that are shaped as conical frustums;

FIG. 4B illustrates the shaped charge having the asymmetric initiation insert with two channels that are shaped as cylinders;

FIGS. 5A to 5C illustrate the location of the channels made in the body of the asymmetric initiation insert for a varying number of channels;

FIGS. 6A and 6B illustrate partially open channels made in the body of the asymmetric initiation insert;

FIG. 7 illustrates in more detail the top and bottom surfaces of the asymmetric initiation insert;

FIG. 8 illustrates a perforating gun system having a gun that includes the shaped charge with the asymmetric initiation insert;

FIG. 9 shows a slot formed into the casing by the shaped charge having the asymmetric initiation insert;

FIG. 10 illustrates the relative position of the perforating gun inside the casing of a well and the various angles at which the shaped charges of the perforating gun are oriented;

FIG. 11 illustrates actual slots formed in the casing of the well with the shaped charges having the asymmetric initiation insert;

FIG. 12 illustrates the sizes and angle distribution of the slots formed in the well's casing with the shaped charges of FIG. 4A;

FIG. 13 illustrates the sizes and angle distribution of the slots formed in the well's casing with the shaped charges of FIG. 4B; and

FIG. 14 is a flowchart of a method for making a shaped charge having the asymmetric initiation insert.

DETAILED DESCRIPTION

The following description of the embodiments refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. The following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims. The following embodiments are discussed, for simplicity, with regard to a perforating gun system used for perforating a casing in a well. However, the embodiments discussed herein may be used for guns in another context.

Reference throughout the specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification is not necessarily referring to the same embodiment. Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.

According to an embodiment, a shaped charge includes, in addition to a case, an explosive material, a liner, and a booster material, an asymmetric initiation insert that makes (1) the explosive material to be initiated from at least two different locations, and (2) the initiation to be asymmetrical relative to a longitudinal axis Y of the shaped charge's case. The longitudinal axis Y may be a symmetry axis for the case, but not for the asymmetric initiation insert. In one application, the longitudinal axis is a symmetry axis for each element of the shaped charge, but for the asymmetric initiation insert. The asymmetric initiation insert may be made of an inexpensive material, for example, plastic, resin, or even a metal. In one application, the asymmetric initiation insert may be 3D printed. In another application, the asymmetric initiation insert may be added to any existing shaped charge case, i.e., any shaped charge can be retrofitted to have the asymmetric initiation insert. The asymmetric initiation insert can be added manually or automatically by a robot to the shaped charge's case. The details of the asymmetric initiation insert are now discussed in more detail with regard to the figures.

FIG. 2 shows a shaped charge 200 having a case 210 that has a base 212 and an open top region 214. The base 212 has a passage 216 that fluidly communicates the exterior of the case 210 with an interior chamber 218, which is defined by the lateral wall 211 of the case 210. The passage 216 of the base 212 is connected to a conduit 219, provided on the outside of the case, and configured to receive a blast from a detonator cord 217. The conduit 219 has an internal chamber that together with the passage 216 are configured to receive a booster material 232, as discussed later. In one application, the booster material 232 partially extends into the passage 216.

An asymmetric initiation insert 220 is placed inside chamber 218, close to the base 212. The insert 220 is shaped in this embodiment to have a frustoconical body, i.e., a truncated cone. In one application, the top surface of the frustoconical body is curved (e.g., convex) and the bottom surface is flat. In one application, the asymmetric initiation insert 220 is in direct contact to the base 212. Although the asymmetric initiation insert 220 is shown in FIG. 2 to be placed in direct contact with the base 212, in another embodiment, as illustrated in FIG. 3, the asymmetric initiation insert 220 is placed away from the base 212. For the embodiment illustrated in FIG. 3, there is a space 222 between the asymmetric initiation insert 220 and the wall 211 of the case 210 all around the insert 220. The asymmetric initiation insert 220 can be placed to be away from the wall 211 either by first packing part of the explosive material 230 on the base 212 and then adding the asymmetric initiation insert 220, or by manufacturing the asymmetric initiation insert 220 to have small spacers or legs 224, which are configured to extend from the insert and sit directly on the base 212 of the case 210.

Returning to the embodiment shown in FIG. 2, the explosive material 230 is placed over the asymmetric initiation insert 220, and a liner 240 is added over the explosive material 230, to fix the explosive material between the insert 220, the wall 211, and the liner 240. The volume of the chamber 218 is thus fully loaded with the explosive material 230. To achieve a blast connection between the detonation cord 217 and the explosive material 230, the booster material 232 may be placed inside the passage 216. The booster material 232 ensures that the fire wave that is initiated by the detonation cord 217 propagates inside the case 210, toward the explosive material 230. The explosive material 230 and the booster material 232 may include any one or more of the following materials: RDX, HMX, HNS, PYX, NONA, ONT, TATB, HNIW, TNAZ, PYX, BRX, PETN, CL-20, NL-11, or any another suitable explosive known in the art.

To allow the fire wave to propagate from the cord 217 to the explosive material 230, the asymmetric initiation insert 220 may have two or more channels 226 that extend through the entire body of the insert (FIG. 2 shows only one channel due to the angle of the view). In one embodiment, the booster material 232 is in direct contact with the channels 226. FIGS. 4A and 4B show the insert 220 having two channels 226-1 and 226-2 that extend from a top surface 220A to a bottom surface 220B of the insert. In the embodiments shown in FIGS. 4A and 4B, each channel is fully formed inside the body 221 of the insert 220. Further, the embodiment shown in FIG. 4A has each of the channels 226-1 and 226-2 shaped as a conical frustum, with the smaller diameter toward the base 212 of the case 210, or toward the bottom surface 220B of the insert 220, and the larger diameter toward the opening 214 of the case 210, or toward the top surface 220A of the insert 220. In this way, two initiation points 228A and 228B are provided for the explosive material 230.

The two initiation points are asymmetrical, i.e., they are not provided on the longitudinal axis Y. Further, the two initiation points are provided while the base 212 of the case 210 has only one passage 216. In addition, the two initiation points 228A and 228B are on the top surface 220A of the body 221, i.e., within the top surface 220A. The embodiment illustrated in FIG. 4B has the two channels 226-1 and 226-2 shaped as cylinders, i.e., having a constant diameter along their lengths. The angle α between (1) each longitudinal axis of the channels 226-1 and 226-2 and (2) the axis Y, which is normal to the base 220B of the insert 220, is the same. The angle may take any desired value. FIGS. 4A and 4B further show that an interface 250 between the side and bottom surfaces of the insert 220 and the case 210 may be so small that no explosive material 230 can fit there. This means that the insert 220 may be manufactured to exactly fit at the bottom of the case 210. However, if some explosive material is desired to be present at that interface, the insert 220 size may be modified to achieve such clearance.

The number of the channels 226 made in the body 221 of the insert 220 may vary from 2 to N, where N is a natural number between 3 and 30. The angular distribution of the channels 226 relative to the top surface 220A is illustrated in FIGS. 5A to 5C. More specifically, FIG. 5A shows only two channels 226-1 and 226-2 located opposite to each other, i.e., making a 180 degrees angle on an angular axis. FIG. 5B shows four channels 226-1 to 226-4 formed into the top surface 220A, each adjacent pair of channels making a 90 degrees angle relative to an angular axis. FIG. 5C shows an embodiment in which there are three channels 226-1 to 226-3 on the top surface 220A, each two adjacent channels making an angle of 120 degrees. It is noted that in one embodiment, it is preferred that the number of channels used are distributed with the same angular distance. However, those skilled in the art would understand from this disclosure that is also possible to change these angles if the shape of the perforation hole in the casing of the gun system needs to be adjusted or changed. The distribution of holes made in the base 220B of the body 221, which correspond to the channels 226, would be similar to those made in the top surface 220A shown in FIGS. 5A to 5C. These bottom holes are illustrated by the dash lines in the figures. However, the difference is that the bottom holes are distributed closer to the central point of the base than the top holes. FIGS. 5A to 5C also show that the top and bottom holes that correspond to opposite channels, if projected on the same plane, would lie on the same line.

While FIGS. 4A and 4B show that the top surface 220A of the insert 220 is convex, it is also possible to have the top surface shaped to be concave or even flat. A distance D between the top point of the top surface 220A and the vertex 242 of the liner 240 (see FIG. 4A) can be selected so that the desired slot-type perforation is obtained in the casing of the gun system. The channels 226 may be fully filed with the explosive material 230, the booster material 232, or with a combination of the two materials.

While FIGS. 4A to 5C show the channels 226 being fully formed within the body 221 of the insert 220, it is also possible, as illustrated in FIGS. 6A and 6B, to have the channels only partially formed within the body 221. More specifically, FIGS. 6A and 6B show that a side of the channels is open to the ambient, i.e., the channel is not fully enclosed by the body 221. While FIGS. 6A and 6B show only two channels being partially exposed to the ambient, any number of the channels in a given insert may be exposed to the ambient. FIG. 6B further shows that about half of the channel's cross-section is formed in the body 221. However, any percentage of the channel's cross-section may be formed within the body 221. Note that in one embodiment, when the insert 220 is placed inside the case 210, the lateral sides of the insert 220 directly contact the internal surface of the case 210, i.e., there is no explosive material 230 at an interface between the sides of the case 210 and the sides of the insert 220. However, if the configuration shown in FIG. 6A is implemented, i.e., the channels 226 of the insert 220 are open to the ambient, then the explosive material may be present between the sides of the case 210 and the open channels 226.

FIG. 7 shows a longitudinal cross-section of the insert 220, having two channels 226-1 and 226-2. The top surface 220A is shown to be curved. The top surface 220A can be parametrized as it is selected to describe a desired curvature. For example, it is possible that the top surface 220A is part of a sphere having a given radius R. The radius R can be in the mm or cm range. In another embodiment, the top surface 220A can be described as part of an ellipse, which is characterized by a semi-minor axis a and a semi-major axis b. In yet another embodiment, the top surface 220A can be described as part of a parabola, which is characterized by three parameters a, b, and c. Other shapes may be selected for the top surface 220A. The bottom surface or base 220B may be selected to be planar, or to have any other profile that will match the internal wall of the shaped charge base. It is noted that the shape of the insert 220 may be selected to intimately match the inside of the base and lateral walls of any shaped charge.

The embodiments discussed herein illustrate various possibilities of providing two or more initiation points for the explosive material 230. Also, the embodiments discussed herein alter the speed of the explosive initiation at the different points so that the shockwave and pressure generated by the explosion of the explosive material 230 does not happen in a radial or circular pattern, as with the traditional shaped charge of FIG. 1, thus generating a jet 140 having a non-circular shape, which is responsible for the slot-type perforation in the casing of the gun system and the channels in the formation. In addition, the insert 220 discussed herein can be implemented in any existing shaped charge, and does not require expensive or difficult additional manufacturing steps when loading the case of the shaped charge.

Because this novel insert 220 would make the shaped charge 200 to generate a slot-type perforation into the casing of the gun system, it is possible to orient the insert to obtain the slot-type oriented in a desired way relative to the casing of the gun system. In this regard, FIG. 8 shows a perforating gun system 800 that includes a first perforating gun 810, a second perforating gun 820, and a connecting or tandem sub 830 that physically connects the two perforating guns to each other. The perforating gun 810 has a casing 812 that fully encloses the various shaped charges 200-I provided inside the gun. The shaped charges 200-I are distributed in this embodiment along a spiral inside the casing. The figure shows that a first shaped charge 200-1 has the first and second channels 226-1 and 226-2 (only the first channel is visible in the figure) arranged along a line 814, the second shaped charge 200-2 has the two channels arranged along a line 816, and the shaped charge 200-I has the two channels arranged along a line 818. The three lines 814 to 818 are shown in the figure having different orientations. However, the inserts 220 may be oriented inside the corresponding shaped charges to obtain the same orientation of the lines 814 to 818. This orientation is related to the desired orientation of the slot-type perforations, which is schematically illustrated in the figure with the corresponding slots 815 to 819. It is noted that the longitudinal axis of each slot is substantially perpendicular to the line that passes through the corresponding two channels in this embodiment. These slots are expected to be formed in the casing 812 of the gun 810, corresponding to each shaped charge, as schematically illustrated in FIG. 9. Thus, depending on the needs of the well's operator, the orientation of the slots in the casing can be controlled by the orientation of the insert 220 in the shaped charge 200. For this purpose, the insert 220 can be marked with an orientating feature upon its surface, for example, a tab, wing, slot or similar mark, to indicate the orientation of its channels, so that the insert can be clocked accordingly to the case of the shaped charge and/or the casing of the gun.

The capabilities of the inserts 220 discussed above have been tested as now discussed. FIG. 10 shows in transversal cross-section the gun 810, its casing 812, a single shaped charge 200 having an insert 220, all of which are placed in a casing 1010 of a well. The well is horizontal and thus, the casing 812 of the gun 810 sits with a bottom portion on the casing 1010 of the well. This means that a fluid 1020 inside the well's casing has a maximum volume at 180 degrees along an angular axis ANG, and zero volume at the origin of the axis ANG. The figure shows various angular positions around the casing 1010 and these positions correspond to the plural shaped charges (not shown) included in the one or more guns 810. It is noted that the amount of fluid between the gun's casing 812 and the well's casing 1010 negatively impacts the well perforation as the jet formed when the shaped charge is fired loses energy when interacting with the fluid 1020.

FIG. 11 shows actual slots 817 formed in plural well's casings 1010 for various angles, which are listed on the left side of the figure, for each casing. Further, the slots 817 at the left of each casing were made with the configuration of the insert shown in FIG. 4A (i.e., channels that increase in diameter toward the top surface 220A of the insert 220) while the slots 817 at the right of each casing where made with the configuration of the insert shown in FIG. 4B (i.e., channels that have a constant diameter). It is noted that the shape of the slots 817 is much closer to a rectangle than a circle, which is the desired goal of the insert 220.

FIG. 12 shows a table with the results for various shots that use the configuration of the insert shown in FIG. 4A. FIG. 12 shows the slots 817 obtained for multiple shots, each shot being characterized by the phasing angle (the angles shown in FIG. 10), and the water clearance (the distance between the exterior of the casing of the gun and the interior of the casing of the well). Each slot is characterized by a long axis L1 of the hole made in the casing and a short axis L2 of the same hole, i.e., the length and width of the slot. FIG. 13 shows similar results when the insert shown in FIG. 4B is used. It is noted that in both cases, the slots are close to a rectangle, as desired.

FIG. 14 illustrates a method for assembling an asymmetric initiated shaped charge 200. The method starts in step 1400 with providing the case of the shaped charge. In optional step 1402, the booster material 232 is placed in the passage 216. In step 1404, the insert 220 is placed inside the case 210, by inserting it from the open end 214 until reaching the base 212. The insert 220 may be simply left as is inside the case 210, or it may be attached with a glue like substance to the inside of the case. In step 1406, either the booster material 232 or the explosive material 230 may be placed inside the channels 226 or both materials may be placed in a desired proportion. In optional step 1408, the insert 220 is clocked relative to a longitudinal axis of the gun to generate the slot-type perforation with a desired orientation relative to the longitudinal axis. In step 1410, a desired amount of the explosive material 230 is placed inside the case 210, over the insert 220. In step 1412, the liner 240 is placed over the explosive material 230 to seal it inside the case 210.

The disclosed embodiments provide methods and systems for generating a slot-like hole perforation into a casing of a well, by using at least an asymmetric initiated shaped charge. It should be understood that this description is not intended to limit the invention. On the contrary, the exemplary embodiments are intended to cover alternatives, modifications and equivalents, which are included in the spirit and scope of the invention as defined by the appended claims. Further, in the detailed description of the exemplary embodiments, numerous specific details are set forth in order to provide a comprehensive understanding of the claimed invention. However, one skilled in the art would understand that various embodiments may be practiced without such specific details.

Although the features and elements of the present exemplary embodiments are described in the embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the embodiments or in various combinations with or without other features and elements disclosed herein.

This written description uses examples of the subject matter disclosed to enable any person skilled in the art to practice the same, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the subject matter is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims. 

What is claimed is:
 1. A shaped charge for making a non-circular perforation into a casing, the shaped charge comprising: a case having a side wall that extends between an open top region and a base; an asymmetric initiation insert configured to fit within the case; an explosive material placed over the asymmetric initiation insert and in contact with the side wall of the case; and a liner placed over the explosive material, to hold the explosive material within the case, wherein the asymmetric initiation insert has a body that includes first and second channels that extend from a bottom surface to a top surface of the body, so that a detonation at the bottom surface is directed to first and second initiation points, that correspond to the first and second channels.
 2. The shaped charge of claim 1, wherein the top surface of the body is convex.
 3. The shaped charge of claim 1, wherein the top surface of the body is part of a sphere of a given radius R.
 4. The shaped charge of claim 1, wherein the asymmetric initiation insert fits tightly over the base and side wall of the case so that no explosive material is present at an interface between the asymmetric initiation insert and the case.
 5. The shaped charge of claim 1, further comprising: a booster material placed in a conduit formed in the base of the case, wherein the conduit is configured to drive a flame from the booster material to the first and second channels of the asymmetric initiation insert.
 6. The shaped charge of claim 1, further comprising: a booster material placed in a conduit formed in the base of the case, wherein the booster material is in direct contact with the first and second channels.
 7. The shaped charge of claim 1, wherein each of the first and second channels is fully formed within the body of the asymmetric initiation insert.
 8. The shaped charge of claim 1, wherein each of the first and second channels is partially open to a side of the asymmetric initiation insert.
 9. The shaped charge of claim 1, wherein the first and second channels are cylinders having a constant radius.
 10. The shaped charge of claim 1, wherein the first and second channels are conical frustums.
 11. A perforating gun for perforating a casing in a well, the perforating gun comprising: a casing; and a shaped charge provided within the casing and configured to make a non-circular perforation into the casing, wherein the shaped charge includes an asymmetric initiation insert having a body that includes first and second channels that extend from a bottom surface to a top surface of the body, so that a detonation at the bottom surface is directed to first and second initiation points, that correspond to the first and second channels, and wherein the first and second initiation points make the shaped charge to form a non-circular perforation into the casing.
 12. The perforating gun of claim 11, wherein the shaped charge comprises: a case having a side wall that extends between an open top region and a base; the asymmetric initiation insert is configured to fit within the case; an explosive material placed over the asymmetric initiation insert and in contact with the side wall of the case; and a liner placed over the explosive material, to hold the explosive material within the case.
 13. The perforating gun of claim 12, wherein the top surface of the body is convex.
 14. The perforating gun of claim 12, wherein the top surface of the body is part of a sphere of a given radius R.
 15. The perforating gun of claim 12, wherein the asymmetric initiation insert fits tightly over the base and side wall of the case so that no explosive material is present at an interface between the asymmetric initiation insert and the case.
 16. The perforating gun of claim 12, wherein the shaped charge further comprises: a booster material placed in a conduit formed in the base of the case, wherein the conduit is configured to drive a flame from the booster material to the first and second channels of the asymmetric initiation insert.
 17. The perforating gun of claim 12, wherein each of the first and second channels is fully formed within the body of the asymmetric initiation insert.
 18. The perforating gun of claim 12, wherein the first and second channels of the asymmetric initiation insert are cylinders having a constant radius.
 19. The perforating gun of claim 12, wherein the first and second channels of the asymmetric initiation insert are conical frustums.
 20. A method of manufacturing a shaped charge that generates a non-circular perforation in a casing, the method comprising: providing a case for the shaped charge; placing an asymmetric initiation insert within the case; orienting angularly the asymmetric initiation insert relative to the case to achieve a desired orientation of the non-circular perforation relative to the casing; placing an explosive material over the asymmetric initiation insert and in contact with a side wall of the case; and placing a liner over the explosive material, to hold the explosive material within the case, wherein the asymmetric initiation insert has a body that includes first and second channels that extend from a bottom surface to a top surface of the body, so that a detonation at the bottom surface is directed to first and second initiation points at the top surface, which correspond to the first and second channels. 